Over power consumption is performed due to a high illumination using a T5 fluorescent light (deco lamp/slim light) and high electric power bulb in consideration with an imitation of a store such as a commercial store including home. In particular, in the case of an open store built on the ground, it is needed to keep a high illumination state for 24 hours using a luminance discharge light with low power consumption, so that over power is consumed. In addition, an adaptor for a power converter and a high capacity of current DC motor and an inverter having a simple power converter function are used for convenience. So, power consumption increases, and the system is complicated, and more cost is needed.
A method for controlling the level of illumination is classified into a method for adjusting voltage and a method for adjusting a frequency. In the former method, since it is not related with the present invention, the description of the same is omitted. The latter method may be classified into a method for adjusting voltage using a transformer, a method for adjusting voltage using an intermittent pulse and a method for controlling voltage based on a phase control.
The method for using a transformer will be first described. A plurality of taps are installed at a secondary side of a transformer for thereby supplying voltage to a portion which needs lighting. The above method is not easy to continuously adjust brightness, and efficiency decreases. So, this method is not currently used.
The method, which uses an intermittent pulse, is directed at controlling a pulse of a conventional inverter. Since the conversion efficiency of the inverter corresponds to the whole efficiency, an advanced inverter technology is needed. The construction is complicated, so that it may be very expensive.
The method based on a phase control is directed to supplying a current at a certain level of AC voltage using the same device as Triac for thereby adjusting the whole voltage. The control of the power by a phase control is a well known art in the industry. In the case of a phase control, it has a simple construction and a good power conversion efficiency, so that it is widely used for an illumination control.
For example, according to the Korean patent application No. 1984-0005770 (illumination control switch for wall box having a plurality of remote control switches), a lighting apparatus being able to control illumination based on an application of the above technology is disclosed. According to the Korean utility model registration No. 20-0244853, a lighting apparatus being able to control illumination based on another application of the above technology is disclosed. According to the above technologies, a setting unit is provided for setting nominal voltage with respect to a lighting assembly, and a control unit is provided for a phase control at each semi-cycle of an electric power applied. There are further provided a zero point detector for a control unit, and a microprocessor for determining a turn on time of Triac using the same, and a lamp unit. With the above construction, a zero point is detected from a power voltage inputted, and a phase control is performed by a processor, so that illumination is controlled by determining electric power applied to light.
However, the method by a phase control and a reverse phase control method have the following problems.
As shown in FIG. 13, when electric power is supplied based on the phase control method, a very high voltage is initially supplied at a start point of the power supply. Since the voltage supply is performed with a high voltage, voltage impact may occur in the load. In a worse case scenario, the load may be damaged by the voltage impact, and/or harmonic frequency may occur. So as to overcome the above problems, a certain filter is used for thereby decreasing voltage impact and harmonic frequency.
However, the above methods have problems as well. Big noises occur at a coil, which is used for decreasing voltage impact. Such noises may be big problems depending on the kinds of loads. In case that the load is lighting and the lighting is used indoor, the problems are very serious. As shown in FIG. 14, the reverse phase control method may supply non-uniform electric power owing to counter electro-motive force with respect to a blank time period of electric power since a turn off/on time of the control point during the control operation. In lower stages, the control problem increases. Critical errors may occur in the stabilizer of load because of high frequency at a basic control point.
In addition, according to the illumination control method, a triac, SCR, and FET devices are used as power control devices. As an AC voltage/current control method, one cable of the input AC power is connected with one end of the power device, so that the gate terminal of the power control device is turned on and off with a DC signal level, and the AC voltage or current is converted. The above methods do not make any problems with respect to incandescent lamps, such as filament preheating type. However, when the AC voltage is introduced at the lower stages during the dimming control of the above method, a flickering and trembling phenomenon occurs, due to the discharge in the case of fluorescent light, so that the life span of tube may decrease.
So as to overcome the above problems, many studies have been conducted on the peripheral filter circuits during the control of power control devices. In the case of low electric power, since there is a certain limit in the tube voltage current in the above discharge light, the control of the fluorescent light of low power is performed by the illumination controller of the fluorescent light which adapts a dimming exclusive special stabilizer. As shown in FIG. 2, in the conventional dimming apparatus, a power supply unit panel is needed. Since a DC converter is necessarily attached to the stabilizer for a dimming operation, as shown in FIG. 1, there may be many problems in construction, when it is adapted to a facility of conventional fluorescent light. When it is newly adapted, an expensive system control apparatus is needed for thereby increasing the expenditure. Since the change of the electric level is less based on the change of the illumination during the installation, only indirect lighting effect can be obtained irrespective of the effect of cost down of electric power, so that it is impossible to obtain an electric power saving effect. Since a facility construction is additionally needed when the local unit illumination control is needed, the construction of the conventional electric power facility should be changed.